1. Field of the Invention
The present invention relates to an apparatus for sealing an arc-tube, and more specifically, to an apparatus for sealing an arc-tube including a sealing jig for sealing an upper bypass tube of the arc-tube.
2. Discussion of Related Art
Generally, a high intensity discharge lamp (HID lamp) is provided with two electrodes for applying a high pressure to an inside of a sealed arc-tube. A predetermined filling material (for example, a halide, mercury, argon, neon, sodium, or a noble gas, etc.) is ionized by an electric arc passing between the two electrodes, so as to be excited so that emitted light with a spectral energy distribution is generated.
The arc-tube is made of quartz or glass. However, recently, a use of a ceramic, such as alumina, as a material of the arc-tube has increased to satisfy a demand of high efficiency. Bypass tube parts are provided at both sides of the arc-tube, and gas is charged through the bypass tube parts. Electrode pins are inserted into the bypass tube parts. In this case, when the electrode pins are inserted into the bypass tube parts, the bypass tube parts are heated up to a high temperature (for example, 1600° C.) to seal the ceramic arc-tube.
At this time, it is important for the electrode pins to be inserted into the bypass tube parts so as not to be moved. This is because a distance between the two electrode pins arranged at both bypass tube parts of the arc-tube has an influence on the performance (brightness) of the high intensity discharge lamp. During the sealing process, when the electrode pin slips down or shakes, the distance between the two electrode pins becomes different from a designed distance. Therefore, there is a problem in which the performance of a product may be changed.    (Patent Document 1) Korean Laid-open Patent Application No. 2004-0004659 (Published on Jan. 13, 2004)